1. Field of the Invention
The present invention relates to an improved turbocompound scheme, in particular in the field of industrial vehicles.
2. Description of the Related Art
Turbocompound systems have been known since the late 1960's.
For example, U.S. Pat. No. 4,100,742 shows a classical turbocompound configuration, wherein a first turbine stage drives a compressor, while a second turbine stage, usually called power turbine, is geared with the crankshaft in order to help the combustion engine.
A hydrodynamic coupling is commonly used to connect the power turbine to the crank train; this type of connection prevents the torsional vibrations of the crank shaft that are magnified by the high gear ratios of the transmission between crank shaft and turbine to affect the turbine.
The use of clutches, e.g. switchable hydrodynamic couplings to conned/disconnect power turbines to engine crank trains is known art, although it is seldom practiced.
The coupling of an electric motor with a turbo-charger is known in order to obtain a desired increase of compressor speed. However this implies the use of means for storing the energy needed to supply the electric motor.
The coupling of an electric motor, acting as a generator, with a turbocharger is known as well in order to obtain a desired reduction of compressor speed. This in turn implies the use of means for storing the energy generated by the electric machine.